Clockwork

The idea of building a racing motorcycle has changed a lot in 38 years. In 1972, we did everything we could both think of and afford to make our machines more capable of running at the front. Today, much of that is prohibited. To prevent factories from doing the unaffordable, sanctioning bodies now prevent everyone from doing so.

Our little dealership had been roadracing a 1970 Kawasaki 500 production racer—an H1-R—for two years. Now, we wanted to see if we could do better under the AMA’s new 750cc displacement limit. Before 1970, the rules had been 750cc for Harley flatheads, 500cc for everyone else—ohv four-strokes and two-strokes alike. Then, in 1970, the rules had eased, letting all four-strokes go to 750, with two-strokes still at 500cc. This let in the new 750 Triples from BSA and Triumph, Honda’s CB750 and Harley’s curious iron ohv XR-750. And when Suzuki and Kawasaki announced 750 Triples for 1972, the AMA made the limit 750 for all. Top international riders were signed. Nine brands were in competition. Suddenly, by happy accident, AMA had the world’s fastest riders on the world’s fastest bikes on the world’s fastest track—Daytona.

Trouble was, Kawasaki wasn’t going to build and sell a 750 production racer as it had done with the 500 Triple. If I wanted one for my rider, I’d have to build it. At Christmastime, 1971, we received our first shipment of the new 750 H2 streetbikes. I pulled the engine from one and tore into it, eager to know if I had the means to make a racer of it and, if so, whether the necessary work could be done in time for Daytona.

The first point was that the close-ratio gearbox of the H1-R would fit into the H2’s cases. But the primary gear and dry clutch of the H1-R would not. That required removing the rivets joining the H2’s primary gear to its wet clutch’s outer basket then making a steel carrier that would allow me to combine the new primary gear and the H1-R’s proven dry clutch. This would be illegal today; I was changing the internal gear ratios of the stock engine. Bailiff! Take than man into custody!

The dry clutch primary cover from the H1-R would also be usable with a bit of welding and machining.

Next, I knew that the stock crankshaft would not last at racing rpm. Its copper-plated big-end roller cages would overheat and fail like so many I had seen before. Kawasaki had chosen an odd roller size; if I wanted silver-plated roller cages made of good steel, I would have to make them. This, too, would be illegal today—even writing on a stock crankshaft with electric pencil today gets you negative press roughly equivalent to a drug bust. I ordered steel, borrowed a dividing head from a machinist friend and got to it. Rollers came from the same supplier in Germany that had transformed my 1971 H1-R cranks from 50-mile steel lottery tickets to 350-mile certainties. Lots of work at the hydraulic press, at the miller and on the phone. This was how it was supposed to be in those days. All over the U.S., people were building bikes for Daytona. Work is speed.

A raceable chassis had to be constructed—also illegal today. I knew that AMA officials had seen so many variants of the basic H1-R twin-loop frame that they would readily accept anything that was visually similar. Nevertheless, we were not able to play the high-level game of assembling a stock-looking frame from shipped-in boxes of factory pieces but with non-production geometry and working to achieve factory-looking welds. We needed a good chassis that would actually work. I had seen stock 500 chassis in action in production racing; they brought to mind the famous red-and-white fishing lure called the “Wob-L-Rite.” I had also seen stock water-pipe forks participate in frightening brake hop.

The only electronics in those days were the rectifier diodes in the German Krober ignition we planned to use. The throttle cables running from the rider’s grip to the three 35mm Mikuni VM carburetors (also taken from the 500 H1-R) were steel, not insulated copper, as today. There was not a stepper motor in sight. A lot of machining of the cylinders was necessary to mount those VMs and the slip-on exhaust pipe couplers—another offense that would qualify today’s builder for a long term in AMA “Leavenworth.” Non-production induction? Altered induction angle? Off I’d go, a grim-faced officer at either elbow. But in those days, it was just rational work undertaken in the interest of trying to do well in races.

What has changed? Streetbikes in those days were not nearly raceable, and the changes required to make them so were fundamental. Today, production sportbikes are close to raceable as they come in the crate. The problem is not to make them fast—they already are fast. Racing has become a dollars-and-cents show biz that depends on delivering elbow-to-elbow contests that put six or 10 finishers in the same second. Bikes for that kind of contest are really carefully adjusted clocks that must all tick at precisely the same rate. Modern racing rules are what adjust those clocks.